Cut cake into three 10X5-inch pieces. Place one cake layer on serving plate. Spread with half the softened ice cream. Cover with second cake layer. Spread with remaining ice cream. Place remaining cake layer on top. Gently push down. Wrap cake in plastic wrap and freeze at least 4 hours.

Just before serving, combine cream, powdered sugar and remaining 2 teaspoons rum in small chilled bowl. Beat with chilled beaters at high speed until stiff peaks form. Remove cake from freezer. Spread thin layer of whipped cream mixture over top of cake. Place star tip in pastry bag; fill with remaining whipped cream mixture. Pipe rosettes around outer top edges of cake. Place candied cherries in narrow strip down center of cake. Sprinkle colored sugars over rosettes, if desired. Serve immediately.